The void that gets created by engaging in an activity that seems like it will be short but ends up taking up huge amounts of time. Like watching video on YouTube, or browsing definitions on Urban Dictionary, or playing Halo 3 on Xbox

Tim: I am so tired, last night I was going to bed and grabbed my laptop to check email. Before I knew it I fell into a timesuck on YouTube and it was 2 am.

An uninterruptable quest to find an answer to a problem that should only have taken less than a few minutes to solve. Solving this puzzle is most often unavoidable and attempts to work around the problem generally add more time and more suck.